Weather Data

Degree-Days, Cooling (CDD): A measure of how warm a location is over a period of time relative to a base temperature, most commonly specified as 65 degrees Fahrenheit.

Degree-Days, Heating (HDD): A measure of how cold a location is over a period of time relative to a base temperature, most commonly specified as 65 degrees Fahrenheit.

Population Weighting: Degree-day readings for each (of nine) Census region are multiplied by a corresponding population weight and then summed to arrive at the national population-weighted degree-day figure.

Historical HDD (with estimates for 2006 and 2007)

Year AER NEMS RSTEM

1995 4531 * *

1996 4713 * *

1997 4542 * *

1998 3951 * *

1999 4169 * *

2000 4460 * *

2001 4223 4157 *

2002 4284 4257 *

2003 4460 4432 *

2004 4290 4254 *

2005 4228 4272 4315

2006 * 4094 4124

2007 * 4370 4451

Normal 4524

Historical CDD (with estimates for 2006 and 2007)

Year AER NEMS RSTEM

1995 1293 * *

1996 1180 * *

1997 1156 * *

1998 1410 * *

1999 1297 * *

2000 1229 * *

2001 1245 1287 *

2002 1393 1406 *

2003 1290 1313 *

2004 1232 1258 *

2005 1444 1421 1395

2006 * 1436 1381

2007 * 1293 1239

Normal 1215